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1. LET 1911 25 1 0 TUBE Nine y 6A SHEARWATER NERD Near Eye e Remote e Display User Manual Revision B Shearwater NERD User Manual Table of Contents dil sgere len i1 asic cesstctsisiticsntncansivaicecucnecnsscnandndecansdcipnducsusadcdandtdsecacividcindscsndsnnescnincnensciaaniinanens 5 Pe UM RETRO 5 Basic Operatlon scien is xia RR ER RE RE TREE E E ERE TRE TER RIC REC RR 6 TUNAI oT m X 7 PUI SRI ST A 8 Installing the NERD on your RebresthiBEeuaeisesciiazi casu pst ii ded etc U bp Id had SY dE Feu acini nd rri rndrdca 9 The Main SCFeeh sisxenniasisickinnrinanone ons nanc a cn ERR ERE RD Ein RR Ri ER RR Rr KR 11 abe o diieelu m Em 11 iaa sNrrol NR RETE KETTE aeaa a aa iaa daaarna aiiai 12 THe Center ROW uriding a Eaa EE EEATT AEREA ETAN A a Aaa SAA 14 Center ROW Configuration m nanaii aaaea EEEa aaa Eaa iaiia 15 The Bott m ROW meatier aaa raaraa vende aaa cuta adia aa nadana ia ESI dM tuations 16 info Sree Lssnsinicgntanekiinnknn nnda conn xa ic nino DEC T ER RE ERE ERR RE 18 COM OSS aieauni ixi ndn it rniononirr n uni oOn a AAAA a AAA Mai pA n RR dnin on REL RR RR UR 22 Operating Modes sssssniinix aiino iria wc iwi nain bina CREE RE RR 25 Gauge Modo iinissuinuncinxri d xiooonuoner nf anoo On RO EGER RD RERO nro 27 Mire icd e savant sexes haem acid E 27 Resettable Average Depth
2. Subsequent installations on the same rebreather loop are as simple as opening and closing the cam lever 10 SHEARWATER Shearwater NERD User Manual The Main Screen 2202 221130 1E 1 20 1 22 1 21 Bottom Row Mode Gas amp Deco Info The main screen shows the most important information needed for technical diving Color Coding em Color coding of text draws attention to problems or unsafe situations Sample warning a better gas is available White text indicates normal conditions Can optionally be set to green in the Advanced Configuration menu YELLOW is used for warnings that are not immediately Nn Flashes id dangerous but should be addressed Sample critical alert FLASHING RED is used for critical alerts that could be life continuing to breathe this threatening if not immediately addressed gas could be fatal Color Blind Users The warning or critical alert states can be determined Warnin l without the use of color Warning doesn t flash Warnings display on a solid inverted background Flashes Alert lt gt fine Critical alert flashes Critical alerts flash between inverted and normal text Q3 SHEARWATER Shearwater NERD User Manual The Top Row 220a 221130 220 221130 The top row displays current depth time and decompression stop information Depth Imperial In feet no decimal places Metric In meters displays with 1 decimal place u
3. SHEARWATER Shearwater NERD User Manual The Bottom Row ia UU 10 al l yr The bottom row displays the current mode gas and decompression information Circuit Mode The current breathing configuration One of OC Open circuit when CC available displays in Yellow to indicate bailout condition CC Closed circuit SC Semi closed circuit 2 a gt c rr Sek LJ P 2 Cam Current Gas O2 He The current gas shown as a percentage of Oxygen and Helium Air pes 02 The remainder of the gas is assumed to be Nitrogen 79 N2 PO um 10 O2 In closed circuit mode this gas is the diluent In open circuit Tx 45094 He mode this is the breathing gas 10 50 40 N2 a better deco gas available Displays in Yellow when there is better deco gas available than the current gas No Decompression Limit NDL The time remaining in minutes at the current depth until decompression stops will be necessary Displays in Yellow when the NDL is less than 5 minutes Once NDL reaches 0 i e deco stops needed the NDL display is just wasting space To address this a few different values can be set to replace the NDL see Dive Setup NDL Display The options are CEIL The current ceiling in the current units feet or meters Flashes Red if you ascend shallower than the current ceiling y Ed 16 SHEARWATER Shearwater NERD User Manual GF99 The raw percen
4. Diving with rebreathers and or diving mixed gases and or performing staged decompression dives and or diving in overhead environments greatly increases the risk of scuba diving You really are risking your life with this activity WARNING This computer has bugs Although we haven t found them all yet they are there It is certain that there are things that this computer does that either we didn t think about or planned for it to do something different Never risk your life on only one source of information Use a second computer or tables If you choose to make riskier dives obtain the proper training and work up to them slowly to gain experience This computer will fail It is not whether it will fail but when it will fail Do not depend on it Always have a plan on how to handle failures Automatic systems are no substitute for knowledge and training No technology will keep you alive Knowledge skill and practiced procedures are your best defense except for not doing the dive of course 4 SHEARWATER Shearwater NERD User Manual Introduction The Shearwater NERD is an advanced technical diving computer for open and closed circuit divers Although we strive to make the NERD easy enough to use without reading the manual please take some time to read this manual to get the best performance from your new computer Diving involves risk and education is your best tool for managing this risk
5. During a dive the average depth can be reset Stopwatch Stopped While on the surface the MAX and AVG values display the maximum and average depth of the last dive The AVG depth displayed on the surface is for the entire dive regardless of whether the reset average depth option was used The dive log also records the average depth for the entire dive 27 QQ SHEARWATER Shearwater NERD User Manual Simple Dive Example The following is a simple rebreather dive that includes decompression stops In this example Diluent Air Imperial units feet are used Max Depth 125 feet for 42 minutes Mode OC CC with External PPO2 Dive Phase Description NERD Display The mode is set to CC and the diluent is set to On the air 21 00 Surface Typically a PPO2 setpoint of 0 7 will be used at the surface Once the descent has started the Petrel will change to dive mode Descending n dive mode dive time starts counting and the surface interval display changes to stop depth and time You ve reached the bottom and can enjoy the fishies wrecks cave mermaids Remember to always monitor your PPO2 Reached The NDL is showing that we have 11 minutes Bottom at this depth until decompression stops will be needed The TTS of 4 minutes is the time to ascend directly to the surface at 33 ft min After a few more minutes the remaining no Decreasing decompression limit NDL time has dropped NDL below
6. 63 Q SHEARWATER Shearwater NERD User Manual Altitude The altitude setting when set to Auto will compensate for pressure D l 6 t ng mgar isplay Setup changes when diving at altitude If all your diving is at sea level TEF then setting this to SeaLvl will assume that surface pressure is MH always 1013 mBar 1 atmosphere Fio Medi A Diving At Altitude When diving at altitude you must set this option to Auto the default setting is SeaLvl Brightness Altitude Flip Screen Further when diving at altitude you must turn the computer on at the surface If the auto on safety feature is allowed to turn the computer on after a dive has started then the computer assumes the surface pressure is 1013 mBar If at altitude this could result in incorrect decompression calculations Change Flip Screen This function displays the contents of the screen upside down This si is used for systems with a permanent connection to a rebreather It lid allows the computer to be worn on the right arm sseuubr4g sun 64 Q3 SHEARWATER Shearwater NERD User Manual Compass Setup Enable If the compass enable is set to off then the compass display does not appear as the first info screen and the Mark Heading menu is not available Calibrate Calibration of the compass may be needed if the accuracy drifts over time or if a permanent magnet or large metal object is mounted very close to the NERD ey
7. The dive log number can be edited This is useful if you want the NERD log numbers to match your lifetime dive count At the Edit Log Number prompt press SELECT to begin editing While editing use MENU to change the value of the currently underlined digit and SELECT to move to the next digit The next dive number will be 1 from the value entered here For example if you enter 0015 then the next dive will be dive number 16 05 86 84 Log Number 0000 SHEARWATER Shearwater NERD User Manual System Setup System Setup contains configuration settings together in a convenient format for updating the configuration before a dive System setup cannot be accessed during a dive However many of the settings are also available during the dive in a single line interface Although all of the settings available in Dive Setup are available in System Setup not all settings in System Setup can be edited in Dive Setup The MENU and SELECT buttons are context sensitive to each sub menu and individual setting When cycling through the sub menus MENU will carry the user to the eem next sub menu while SELECT will allow the user to edit the options in Raye Example this submenu Exile Once the user has pressed SELECT to edit a submenu MENU will cycle the user through the different submenu listings while SELECT will let the user edit those listings Exanple l Once the user has pressed SELECT to edi
8. F02 98 The NERD will see that only one sensor is connected and automatically switch to single sensor mode Calibration Problems One sensor displays FAIL after calibration This could indicate a bad sensor It has failed because the mV output was not in range The sensor could be old or damaged and should be inspected Damage and corrosion to wires or connectors is also a common problem Fix the problem and recalibrate before diving All sensors display FAIL after calibration This could be caused by an accidentally unplugged cable or a damaged cable or connector Also accidentally performing the calibration in air or without a proper oxygen flush could cause this problem A failed calibration can only be fixed by performing a successful calibration CC 21 00 0 PPO2 does not show 0 98 after calibration If you use a calibration FO2 setting of 0 98 and are at sea level you probably expect the calibrated PPO2 to show 0 98 Sometimes you might correctly get a different value like 0 96 or 1 01 This is because weather causes minor changes in barometric pressure For example say a low pressure weather system has reduced the normal 1013mbar barometric pressure to 990mbar The PPO2 in absolute atmospheres is then 0 98 990 1013 0 96 The 0 96 PPO2 result is in this case correct At high altitudes the difference between FO2 and PPO2 will be even larger To see the 06 06 6 current pressure start at the main sc
9. Feature List Depth time and oxygen sensor display e B hlmann decompression model ZHL 16C with gradient factors conservatism e Optional VPM B decompression model Imperial and metric displays e External EXT PPO2 monitoring from 1 or 3 O2 cells Internal PPO2 mode with 2 set points each of which can be set between 4 and 1 5 Digital compass with tilt compenation and true north declination adjustment e A menu system that adapts to diving status e Automatic turn off after 15 minutes on the surface Depth sensor rated to 450 feet 140 meters of seawater Dive Planner e Any combination of oxygen nitrogen and helium Air Nitrox Trimix Open and closed circuit switchable during a dive e 5CC and 5 OC gases e Gases can be changed and added during a dive e CNS tracking e No lockout from violating deco stops e Automatic PPO2 set point switching in internal PPO2 mode configurable Flexible user replaceable battery Almost any AA type e 1000 hour dive log memory e Log downloads and firmware upgrades using Bluetooth 5 QQ SHEARWATER Shearwater NERD User Manual Basic Operation simulated representation of the display The NERD is mounted in front of the face The screen image floats in view for the entire dive showing all information needed for technical recreational or rebreather diving or a 32 TV 12 away The image size is equivalent to a pe Petrel 1 away wale 990 22 190 1 23
10. Up Depth Down 1 3 gt 0 7 Down Depth Next SHEARWATER Shearwater NERD User Manual The menu options are the same for the down setpoint switch Example Up 0 7 1 3 Auto Up Depth 70 ft in TE p 721 Down 1 3 gt 0 7 Auto Down Depth 41ft Up Depth Down 1 3 gt 0 7 The dives starts at the 0 7 setpoint As you descend past Down Depth 70ft the setpoint switches up to 1 3 You finish your bottom time then begin ascending When you ascend above 41ft it switches down to 0 7 Up 0 7 gt 1 3 P Up Depth When a switch is set to Auto you can always manually override the setting at any time during the dive Down 1 320 7 Each auto setpoint switch can occur only once per dive Either switch can be set to auto or manual independent of the other switch The values 0 7 and 1 3 are shown as examples only Other values for the low and high setpoint can be adjusted in the Dive Setup menu Display Setup Units Two options are available Feet Imperial units depth in feet temperature in F Meters Metric units depth in meters temperature in C Brightness H Altitude Brightness Flip Screen Screen brightness can be set to three fixed levels e Low Longest battery life e Med Best mix of battery life and readability High Easiest readability especially in bright sunlight Brightness Altitude Flip Screen Brightness Altitude Flip Screen
11. on If you often use other gases but not on this dive you can enter the gas and turn it off You can turn gases on and off during a dive and you can also add or remove a gas dur ing the dive if needed 49 Q SHEARWATER Shearwater NERD User Manual 50 Dive Planner INTRODUCTION e Calculates decompression profiles for simple dives In closed circuit CC mode also calculates open circuit OC bail out BO SETUP Uses the current gases programmed into the NERD as well as the current GF low high settings VPM B dive planning is available on units with the optional VPM B unlock Deco profile is computed for the current circuit mode CC or OC ON THE SURFACE Enter the dive bottom depth bottom time respiratory minute volume RMV and PPO2 closed circuit only en ose Pu Enter Bottom Time Note Residual tissue loading and CNS from recent de minutes D in dives will be used in calculating the profile Max 180 DURING A DIVE eo Chanse Computes the decompression profile assuming the ascent Dive Plan Setup will begin immediately There are no settings to enter RMV is last used value LIMITATIONS The NERD Dive Planner is intended for simple dives Multi level dives are not supported The NERD Dive Planner makes the following assumptions Descent rate is 60ft min 18m min and the ascent rate is 33ft min 10m min For OC the gas in use will be the gas with the highest PPO2 less than 1 40 for th
12. 03 2010 23 52 24FFCCAD 22 06 03 2010 04 23 24FFCCAD 21 06 02 2010 23 45 Graph Details Total Length 119 min MaxDepth 133m GF 30 85 CNS 0 tc 4o hoso 30 Select the aes file and then click start Select a firmware file 21x Update Firmware Look in 23 Petrel Firmware S er E3 i Petrel v06 aes Ia Petrel v06 aes SelectFile My Recent Documents Desktop My Documents My Computer j LS File name etrel vB aes Open Files of type Shearwater Firmware aes X Cancel Zi It will take approximately 5 minutes to send the new firmware The NERD screen may flicker or go black for up to 1minute during the update Do NOT remove the battery during this time After the update the NERD will reset and indicate that the decompression tissues have been cleared This screen will also indicate whether the update was a success or failure Bluetooth trouble shooting available at http www shearwaterresearch com support Or contact Shearwater Research at info shearwaterresearch com for assistance 7o Q SHEARWATER Shearwater NERD User Manual Changing the Battery NOTE A large coin or washer is required for this section Turn off the NERD It is a good practice to turn off the NERD before removing the battery If removed while on then there is a small chance about 1 in 5000 that the deco tissues will be corrupted The NERD detects this using a cyclic r
13. 1 25 oo 10 50 0 56 The image appears here allowing your eyes to stay focused at a distance The image appears about 12 4m away keeping your vision focused on the dive You do not need to refocus closer to read the display This means near vision correction is not needed nor wanted a plus for those with aging eyes or who wear reading glasses 6 Q3 SHEARWATER Shearwater NERD User Manual Turning On To turn the NERD on press both buttons at the same time Press both buttons at the same time 7 Q3 SHEARWATER Shearwater NERD User Manual Buttons Two piezo electric buttons are used to change settings and view menus Except for turning the NERD on all operations are simple single button presses SELECT right MENU left button button make using the NERD easy MENU button Left e From main screen brings up the menu e namenu moves to the next menu item Editing a setting changes the setting s value SELECT button Right From main screen steps through information screens e Inamenu performs command or starts editing Editing a setting saves the setting s value BOTH BUTTONS When NERD is off pressing MENU and SELECT at the same time will turn the NERD on e No other operation requires pressing both buttons at the same time Button Hints When in a menu button hints label each button For example the hints to the right tell us use MENU to change t
14. 4 3 33 3 33 8 N SELECT button Info screens provide additional information that does not fit on the main screen Starting from the main screen the SELECT right button steps through the info screens When all info screens have been viewed pressing SELECT again will return to the main screen Info screens time out after 10 seconds returning to the main screen Pressing the MENU left button will also return to the main screen The info screen content is optimized for each mode Set the NERD to the mode you will be using e g OC and step through the info screens to get familiar with the content The next section describes the individual values shown on the info screens 8 QQ SHEARWATER Shearwater NERD User Manual Average Depth Displays the average depth of the current dive updated once per second When not diving shows the average depth of the last dive Average Depth in Atmospheres AvgATM The average depth of the current dive measured in absolute atmospheres i e a value of 1 0 at sea level When not diving shows the average depth of the last dive Maximum Depth The maximum depth of the current dive When not diving displays the maximum depth of the last dive CNS Toxicity Percentage Central Nervous System oxygen toxicity loading percentage Flashes Red when 100 or greater The CNS percentage is calculated continuously even when on the surface and turned off When deco tissues
15. True North Calibrate Factory Reset Exit True North Offset is 15 Set to current pos Reset to 0 Exit Next Shearwater NERD User Manual System Setup Date The first System Setup changeable option is Date which allows ar ee the user to set the current date Unlock i Load Upgrade Reset to Defaults Time The next System Setup changeable option is Time which allows the user to set the current time The format can be set to AM PM or 24 hour time Load Upgrade Reset to Defaults Unlock Code The next System Setup changeable option is Unlock which allows the user to enter in an unlock in order to change models and to set other features Load Upgrade Reset to Defaults 8567000000000000 Load Upgrade Load Upgrade Reset to Defaults Change Unlock Use this option to load firmware upgrades This starts a Bluetooth connection and then waits for commands from a laptop or desktop computer See the section Firmware Upload and Dive Log Download for detailed instructions Reset to Defaults The final System Setup option is Reset to Defaults This will reset all user changed options to factory settings and clear the tissues on the NERD Reset to Defaults cannot be reversed Load Upgrad Note This will not delete dive logs or reset dive log numbers Reset to Defaults Exit Reset 66 Q3 SHEARWATER Shearwater NERD User Manu
16. are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy If not installed and used in accordance with the instructions it may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by tuning the equipment off and on the user is encouraged to try and correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the distance between the equipment and the receiver Connect the equipment to outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio TV technician for help Any changes or modifications not expressly approved by the party responsible for compliance could void the user s authority to operate the equipment Caution Exposure to Radio Frequency Radiation This device must not be co located or operating in conjunction with any other antenna or transmitter Contains TX FCC ID T7VEBMU Industry Canada Warning b Canada Industry Canada IC This device complies with RSS 210 of Industry Canada Operation is subject to the following two conditions 1 this device may not cause interference a
17. not unusual to get this error immediately after submerging with a manual CCR and a hypoxic mix The first breath after submerging floods the loop with low PPO2 gas The situation is usually resolved by increasing depth such that when the error is noticed the PPO2 is no longer low This condition will also cause the LOW PPO display to appear Here the computer does not have two sensors that have confirming values There is no way to know the actual PPO2 and the average PPO2 will be calculated as 0 11 the lowest value is the most conservative for decompression calculations 45 This message will appear when your internal battery is low for 30 1 30 1 32 1 31 seconds The battery needs to be changed The computer will also flash the battery symbol red 76 QQ SHEARWATER Shearwater NERD User Manual This alarm is a notification that there has either been a very fast 45 ascent for a short period of time or that there has been an ascent of more than 66 fpm 20 mpm maintained for over a minute This 1 30 1 32 1 31 alarm may return after being dismissed if the condition occurs again The alarm occurs when the diver has been above the minimum 45 130 1 32 131 depth for a decompression stop for more than one minute This alarm will only appear once during a dive but it will also appear once on the surface after the dive 45 This alarm will show when the decompression tissues are cleared 1 30 1 32 131 All decompres
18. will display the currently selected value Values from 0 4 to 1 5 are allowed Apress of MENU will increment the setpoint 0 du Ayn 85 86 M Press the SELECT button when Edit Low SP is displayed and the edit Edit Low cp 4 display will be shown Itis set at the lowest valid value for setpoint 4 46 SHEARWATER Shearwater NERD User Manual du Ann Another press of MENU will increment it again If SELECT is pushed the currently displayed setpoint will be selected and the display will return to the Edit Low SP menu item If the highest allowable value 1 5 has been passed the value will return to 0 4 High Setpoint The high setpoint function works exactly like the low setpoint 0 dur 45 function 185 86 84 Edit High SP 1 3 47 QQ SHEARWATER Shearwater NERD User Manual Define Gas The function allows you to set up 5 gases in Closed Circuit and 5 gases in Open Circuit You must be in Open Circuit to edit open circuit gases and you must be in Closed Circuit to edit closed circuit diluents For each gas you can select the percentage of oxygen and helium in the gas The remainder is assumed to be nitrogen Pushing SELECT when Define Gas is displayed presents the function to define gas number 1 85 86 84 10C On 99 00 Pushing the MENU button will display the next gas Pushing SELECT will allow you to edit the current gas The gas contents are edited one digit at a time The un
19. 00 Max Depth 90 meters for 20 minutes Metric units meters are used Dive Phase Description NERD Display Best practices include checking your gas lists before each dive This screen is available in On 10 50 Setup the System Setup menu CC Gases For this dive the only CC diluent is trimix 10 50 10 O2 50 He 40 N2 For the OC bailout gas list several gases are Setup needed OC Bailout Gases We will verify that we are carrying enough of each gas when we plan the dive It is also prudent to ensure all other settings are correct before starting the dive Buhlmann GF ZHL 16C Verify Conserv GF 20 80 Settings Although gases and some settings can be Last Stop 3m changed underwater it is best to have them NDL Display GF99 right from the start Use the dive planner to check the total runtime decompression schedule and bailout out gas quantity needed For CC dives both the closed circuit CC and Plan Dive bailout BO plans are displayed The bailout amp Bailout plan also includes how much gas is needed The on board deco planner is limited in functionality so for complex dives we recommend planning using desktop or smartphone dive planning software 50 00 2060 D 12 21 00 9 10 50 591 Continued on next page 30 Q SHEARWATER Shearwater NERD User Manual Complex Dive Example continued Dive Phase Description NERD Display If the PPO2 sensors need calibration follow the instructions from your rebreat
20. 10ft 3m last stop depth At this Alert depth is setting you may perform the last stop at 20ft 6m with no shallower than the penalty The only difference is that the predicted time to surface 90ft stop depth will be shorter than the actual TTS since off gasing is occurring slower than expected There is also an option to set the last stop to 20ft 6m if you wish Surface Interval When on the surface the STOP DEPTH and TIME are replaced by a surface interval display 2hr Abn Shows the hours and minutes since the end of your last dive Above 4 days the surface interval is displayed in days The surface interval is reset when the decompression tissues are cleared See the section on Tissues Cleared Sample surface main screen showing the surface interval 13 SHEARWATER Shearwater NERD User Manual The Center Row The center row displays PPO2 PPO2 units are absolute atmospheres 1ata 1013mbar The layout varies depending on the current mode Mode MenuSetup CenterRow Display E Salinity Fresh Open Circuit OC Gas PPO2 Closed Circuit with Salinity Internal PP02 Mode PPO2 Setpoints Low SP High SP CC Internal Setpoint PPO2 Closed Circuit with Salinity Fresh External PPO2 Mode Ext 29 M 28 PPO2 Monitoring CC External Measured PPO2 Next Edit In CC mode PPO2 displays in Flashing Red when less than 0 40 or greater than 1 6 In OC mode PPO2 displays in F
21. 21 4 22 21 99 00 20 40 Next Off Gases are Magenta 01 4 22 21 Select Active Gas is White SHEARWATER Shearwater NERD User Manual Switch to OC CC Depending on the current computer setting this selection will show as either Switch CC gt OC or Switch OC gt CC Pressing SELECT will select the displayed mode for decompression calculations When switching to open circuit while diving the most appropriate open circuit gas will become the breathing gas for 0 l5 r n calculations jg T Y At this point the diver may want to switch to a different gas but since the diver may have other things to deal with the computer will make a ut h best guess of which gas the diver would choose On computers with external oxygen sensor monitoring there is also dur ASi an option to set the computer to calculate decompression predictions 85 86 84 using semi closed circuit This is enabled in the System Setup menu l ie You can also switch to from CC to OC on a fixed PPO2 model In that case the computer will use the user entered high and low setpoints Dive Setup The Dive Setup menus are available both on the surface and when diving The values in Dive Setup can also be accessed in the Systems Setup menu but the System Setup menu is not available when 85 86 84 diving Pressing SELECT will enter the Dive Setup sub menu Low Setpoint This item allows you to set the low setpoint value It
22. 5 minutes and is now highlighted in yellow Continued on next page 28 QQ SHEARWATER Shearwater NERD User Manual Simple Dive Example continued Dive Phase Deco Description NERD Display Once the NDL hits 0 deco stops will be needed which display in the top right corner 12 4 4 2 Also note that the NDL location is now 1 IK 1 M 1 20 Needed displaying additional info in this case 5 TTS has increased to include deco stop time Ascending It is safe to ascend to AOft 2 minutes must be spent at this deco stop 82 44 40 2 While ascending the bar graph to the right of the depth shows the ascent rate 30 31 29 Each bar indicates 10 ft per minute 3m min of ascent rate On Deco Missed Deco Stop 41 46 40 Stay at each stop depth until it clears 1 MI If you ascend shallower than the stop depth the display will alarm Acknowledge and clear the warning by pressing the SELECT button 28 30 p Re descend deeper than the stop depth to clear the flashing red text Deco Clear 29 Once all the deco stops have cleared you can 1 65 Clear ascend to the surface to end the dive 25 26 End of example Q SHEARWATER Shearwater NERD User Manual Complex Dive Example The following is a more complex rebreather dive that includes multi gas OC bailout In this example Diluent Trimix 10 50 Bailout gases 10 50 21 00 and 50
23. T 67 Advanced Configuration E NET 68 Firmware Upload and Dive Log Download 1 eere rene nennen nnn 69 Changing th Battery iussnniaonnssinins taion sick ic a cic ribi ar 71 Battery eic NETTE AE EEEa E Eas 72 Threading the NERD s StrapP sssnssnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nnmnnn nnn nnn 73 Disassembling the Loop Mount sscsssssessssensssennssenesseceeseneessenesseneeseenesseneesnenessenees 74 Tissues Clearedius usa usiaaixiskiorciaibnn pw ORO GRO RODEO REOR COUGH Ec 75 Error Displays ussesassxim cxi Dn Erici wc wi bn ERR ERR CREE n RF RR 76 Storage and Maintenance susce dicio nro anon nion bcr GR RERO 78 Ca dnos onracnr cannon REGERE GRE PR GEO ERE ED ER ERREUR E RR 78 Fischer PlrisOLt usines ass iion a CREER AR AT REN ER E EF RD RR RT T ERR ER ERA nan a 78 Specificatl flis uisssu anamixkiFE RR EMFFEENE EE E SUE LER ER RR GNE THENE A SE REI LU RR ERES R VE SUR DR AEEAMARR MH I R NH RR V Ena ini NE 79 d dA quiso MERE NN RNC 80 industry Canada VVSERIFIE essem csse cic bavt dpa edn ta Dual dee tied oend ta a ad ed ocu dM sul ca thc rl Rd 80 3 Q SHEARWATER Shearwater NERD User Manual DANGER This computer is capable of calculating deco stop requirements These calculations are at best a guess of the real physiological decompression requirements Dives requiring staged decompression are substantially more risky than dives that stay well within no stop limits
24. a PPO2 Mode Display Log Upload Log Q3 SHEARWATER Dive Setup Deco Setup Center Row 00 Gases Shearwater NERD User Manual The following sections show the menu structure in various operating modes Gauge Menu Structure si Reset Avo Depth Sub Menus Dive Setup Upload Log Edit Log Number Dive Logt System Setupt System Setup Advanced Config 38 SHEARWATER Shearwater NERD User Manual 39 Basic Setup Before using the computer there are several things that need to be configured This is not an exhaustive list of the pre requisites for diving the system but a suggestion of key tasks On a system with external oxygen sensors calibrate the oxygen sensors In the System Setup menu set the units to metric or imperial also set the date and time Depending on the model of computer enter the gases that you will use for the closed circuit portion of your dive and or enter the gases for you will use for open circuit The system will use the gases that are available in the order of oxygen content during the Time To Surface TTS prediction The system will use the next available gas that has a PPO2 of less than 1 0 for closed circuit diving If the computer is in open circuit or is switched to open circuit during a dive the system will calculate the TTS based on the configured open circuit gases that are availab
25. age A of the M value Gradient x Gradient Factors GF are F UN detined between zero and one 2 M valua GF Lo 0 lt GF lt 1 5 o Gradient iS t generates T F 5 first stop A Gradient Factor of 0 represents E 7 A j the ambient pressure line P a 5 ie A Gradient Factor of 1 represents m T Pi the M value lina c ey Pd mear function T e for gradual Gradient Factors modify the E E E ud change in ariginal M value equations for E P oe Gradient conservatism within the E p e Factors decompression zone R e e The lower Gradient Factor value GF Hi surfacing value GF Lo determines the depth of Maintains safety margin Firat the first stop Used to generate ap deep stops to the depth of the deepest possible deco stop Ambient Pressure solute amp Graph from Erik Baker s Clearing Up The Confusion About Deep Stops 40 SHEARWATER Shearwater NERD User Manual 4 Menu Reference Turn Off The Turn Off item puts the computer to sleep While sleeping the screen is blank but the tissue contents are maintained for repetitive diving The Turn Off menu item will not appear during a dive on any model It will also not appear after a dive until the Time has expired to allow for a continuation dive Calibration The Calibrate menu will only appear when in CC mode with the PPO2 mode set to Ext This menu calibrates the mV output from the oxygen sensors to PPO2 Upon selecting the calibrat
26. al Advanced Configuration 1 Advanced configuration contains items that will be used infrequently and can be ignored by most users They provide more detailed Enter Adv Config configurations Reset Adv Config System Info The first screen allows you to enter the advanced configuration area Battery Jats or to set the advanced configurations settings to their default Done Title Color The title colors can be changed for added contrast or visual appeal NV Confio Default is Cyan with gray white and blue also available Title Calor End Dive Delay 060s End Dive Delay Bat Icon Surf Warn g Gas Select Classic Sets the time in seconds to wait after surfacing before ending the current dive Next Edit This value can be set from 20 seconds to 600 seconds 10 minutes Default is 60s This value can be set to a longer time if you want brief surface intervals connected together into one dive Some instructors use a longer end dive delay when teaching courses Alternatively a shorter time can be used to exit dive mode more quickly upon surfacing Battery Icon The behavior of the battery icon can be changed here Options are Surf Warn The battery icon displays always when on the surface During dive it displays only if there is a low battery warning Always The battery icon always displays Warn Only The battery icon only appears when there is a low battery warning this is how the Predator operates Gas S
27. are reset the CNS will also be reset PPO2 average PPO2 Only relevant when external PPO2 monitoring is used since other modes already show PPO2 on the center row The purpose of this value is to show what PPO2 is actually being used for decompression calculations no n e p a m When three external sensors are used the NERD votes on the three measured values to decide what is the most likely true PPO2 This value shows the result of the voting Also when using external sensors and you have bailed out to OC the center row continues to display the external measured PPO2 Use this info display to see the OC PPO2 In CC mode displays in Flashing Red when less than 0 40 or greater than 1 6 In OC mode displays in Flashing Red when less than 0 19 or greater than 1 65 19 SHEARWATER Shearwater NERD User Manual Diluent PPO2 Only displayed in CC mode Displays in Flashing Red when the partial pressure of the diluent is less than 0 19 or greater than 1 65 When performing a manual diluent flush you can check this value to see what the expected PPO2 will be at the current depth Fraction Inspired O2 FiO2 The fraction of the breathing gas composed of O2 This value is independent of pressure Tissues Bar Graph The tissues bar graph shows the tissue compartment inert gas tissue tensions based on the B hlmann ZHL 16C model Note that VPM B also tracks tensions in the same way The fastest tiss
28. arwater NERD User Manual Battery Types After changing the battery a screen will prompt for the battery type to be entered The NERD attempts to guess what type of battery is being used If the battery type is incorrect it should be manually edited Having the battery type set correctly is important so that the NERD can give low battery warnings at the proper voltage levels Supported battery types are 1 5V Alkaline The common AA battery type that can be purchased at most supermarkets and electronics stores around the world Not rechargeable Inexpensive and reliable they provide 35 hours of operation Recommended 1 5V Photo Lithium Fairly common but more expensive than alkalines They provide about 55 hours of operation Not rechargeable Good for use in very cold water Recommended 1 2V NiMH Common rechargeable batteries used in digital cameras and photo flashes Can have high self discharge Provide about 30 hours of operation per charge Can die quickly so care should be taken to ensure sufficient charge prior to diving 3 6V Saft The Saft LS14500 lithium batteries provide very high energy density However their high cost makes other battery types a better choice for most users Provide about 100 hours of operation Can die quickly so care should be taken to ensure sufficient charge prior to diving 3 7V Li lon Rechargeable14500 Li lon batteries provide about 35 hours of operation per charge Can be ordered fr
29. derline will show you the digit being edited 0C On Each push of the MENU button will increment the digit being edited When the digit reaches 9 it will roll over to O 05 96 20C On Pushing SELECT will lock in the current digit and move on to the next digit 0 On Pushing SELECT on the last digit will finish editing that gas and bring you 0 back to the gas number Any gases that have both oxygen and helium set to 00 will not be 5 00 displayed in the Select Gas function 0 On 48 QQ SHEARWATER Shearwater NERD User Manual Pushing MENU will continue to increment the gas number Note The A denotes the active gas You cannot delete the active gas If you try it will generate an error You can edit it but cannot set both the O2 and HE to 00 The computer will display all 5 gas entries available to allow you to enter new gases Pressing MENU one more time when the fifth gas is displayed will return you to the Define Gas menu item A Only turn on gases you are carrying Only turn on the gases you are actually carrying on the dive With radio station gases the computer has a full picture of the OC and CC gases you are carrying and can make informed predictions about decompression times There is no need to turn gases off and on when you switch from CC to OC because the computer already knows what the gas sets are You should have the CC and OC gases you are actually carrying turned
30. e bottom gas and 1 61 for deco gases the deco gas max PPO2 can be changed in the Adv Config 1 menu For CC the gas in use will be the gas with the highest PPO2 less than 1 05 The planner will use the configured last stop depth For CC the PPO2 is constant for the entire dive The RMV is the same while diving as during deco Semi closed uses a metabolic offset Q SHEARWATER Shearwater NERD User Manual The Dive Planner does not provide thorough validation of the profile For example it does not check for nitrogen narcosis limitations gas usage limitations CNS percentage violations or isobaric counter diffusion risks due to sudden helium switches The user is responsible for ensuring a safe profile is followed RESULT SCREENS The results are given in tables showing e Stp Stop Depth In feet or meters Tme Stop Time In minutes e Run Run Time In minutes Qty Gas Quantity in CuFt or liters OC and BO only The first two rows are special the first row showing the bottom time and the second showing the ascent to the first stop When diving these two rows are not displayed CC Depth Time RMY P02 Depth Time RMV PO2 150 030 55 1 3 150 030 55 1 3 Ste Ime Run Gas Ste Tme Run Gas Qty 150 bot 30 10 50 30 5 43 36 00 6 70 asc 32 10 50 20 6 49 99 00 6 70 1 33 10 50 10 11 60 99 00 60 2 35 10 50 50 1 36 10 50 Quit Next Quit Example Results Table for Closed Circuit and Bailout If more than 5 stops are ne
31. e on to view the regular info screens Unlike the regular info screens the compass never times out back to the main screen Press MENU left button to return to the main screen Marking a Heading To mark a heading press MENU left button until Mark Heading is displayed then press SELECT right button to mark the current direction The display will then jump back to the compass display The heading is shown as a green triangle E NN ZTA Mark the heading to This feature makes it easy remember the current to determine if you are off direction course ITA When the marked heading When facing the opposite is off screen an arrow direction the reciprocal points the shortest way heading is shown as a red back triangle Only one heading can be marked at a time it can however be changed Once a heading has been marked there is no way to clear the heading arrows from the display 23 QQ SHEARWATER Shearwater NERD User Manual Compass Limitations Like any magnetic compass the compass on the NERD has some limitations Understanding these limitations will help ensure accurate navigation Metal objects permanent magnets and other sources of magnetic interference such as electric motors should be kept away from the compass We recommend comparing the compass accuracy to a known good compass with and without the interfering object in place to see if it has an effect If a small metal object or magnet is attached in a f
32. eco schedule has been adjusted based on the OC gases We are now at 21m having completed a few 21 2 53 21 more deco stops The gas is now displaying in 05 yellow indicating a better gas is available Pressing MENU twice brings up the SELECT GAS menu and pressing SELECT enters it With the new style gas select menu the best gas will already be the initial selection just 2 2 43 press SELECT to make it the active gas l If using the old style gas select menu see the d 09 gas select section for instructions SUUM 1 00 Next Follow the deco stops until they have all 3 1 132 ee cleared Now it is time to ascend and end the dive End of example Q SHEARWATER Shearwater NERD User Manual Menus Press MENU left button to step through the menus Press SELECT right button to execute command or enter sub menu Menus display on the bottom row NO MENU button urn Off m N MENU button e l button Enter Calibrate N MENU button Menus perform actions and allow settings to be changed Starting from the main screen pressing the MENU left button steps through the menus When all menus have been viewed pressing MENU again will return to the main screen Pressing the SELECT right button when a menu is displayed either performs that action or enters a sub menu If no buttons are pushed for 1 minute the menu system will time out returning to the main screen Any
33. eded the results will be split onto on several screens Use the right button to step through the screens For OC or BO profiles a total gas consumption report is given Depth Time RMV PO2 150 030 55 1 3 Gas Usase in CuFt 99 00 14 36 00 14 21 25 7 12 50 0 Quit Gas Usage Report 5 Q3 SHEARWATER Shearwater NERD User Manual The final result screen shows the total dive time the time spent on deco and final CNS CC Depth Time AMY PO2 150 030 55 1 3 CC Summarv Run 61 minutes Deco 31 minutes CNS 34 X Quit Plan BO Results Summary Screen If no decompression is required no table will be shown Instead the total No Decompression Limit NDL time in minutes at the given bottom depth will be reported Also the gas quantity required to surface bailout in CC will be reported CC Depth Time AMY PO2 080 030 65 1 3 No Deco Stops Total NDL at 80ft is 47 minutes Bailout gas quantity ds 4 CuFt Quit Done No Decompression Results Screen Conservatism The conservatism settings GF High and GF Low can be edited in the Dive Setup menu While diving only the GH High value can be edited This allows changing the surfacing conservatism during a dive For example if you worked much harder on the bottom segment than expected you may wish to add conservatism by reducing the GF High setting 52 QQ SHEARWATER Shearwater NERD User Manual NDL Display The NDL Display opt
34. edundancy check CRC so there is no danger However the tissues will be lost and repetitive dives will need to be planned accordingly Remove the battery cap Insert the coin or washer into the battery cap slot Unscrew by turning counter clockwise until the battery cap is free Be sure to store the battery cap in a clean dry space Exchange the battery Remove the existing battery by tilting the NERD computer Insert the new battery positive contact first A small diagram on the bottom of the NERD shows the proper orientation Accepted battery types The Shearwater NERD can accept a wide variety of AA sized batteries The NERD can accept any AA sized or 14500 size battery that outputs a voltage between 0 9V and 4 3V Reinstalling the battery cap It is very important that the battery cap O ring is clear of dust or debris Carefully inspect your O ring for any debris or damage and gently clean It is recommended that you lubricate your battery cap s O ring on a regular basis with an O ring lubricant compatible with Buna N Nitrile O rings Lubricating helps ensure that the O ring seats properly and does not twist or bunch Insert the battery cap into the NERD and compress the battery contact springs While the springs are compressed rotate the battery cap clockwise to engage the threads Be sure not to cross thread the battery cap s threads Tighten the battery cap until snug Do not over tighten the battery cap 7 Q SHEARWATER She
35. elect The style of Select Gas menu Either Classic or New Classic style shows one gas at a time in the large font New style shows all gases at once but in the small font 67 Q SHEARWATER Shearwater NERD User Manual Advanced Configuration 2 This section allows changing of PPO2 limits PP02 PP02 Warning Do not change these values unless you understand the effect l PP02 PP02 All values are in absolute atmospheres ata of pressure 1 ata 1 013 Ie Bar OC Min PPO2 PPO2 displays in flashing red when less than this value Default 0 19 OC Max PPO2 PPO2 displays in flashing red when greater than this value Default 1 65 OC Deco PPO2 The decompression predictions TTS and NDL will assume that the gas in use at a given depth is the gas with the highest PPO2 that is less than or equal to this value Also the suggested gas switches when the current gas is displayed in yellow are determined by this value If you change this value please understand its effect For example if lowered to 1 50 then oxygen 99 00 will not be assumed at 20ft 6m Default 1 61 Note Semi closed SC PPO2 alarms and gas switch depths use the OC values CC Min PPO2 PPO2 displays in flashing red when less than this value Default 0 40 CC Max PPO2 PPO2 displays in flashing red when greater than this value Default 1 60 Note In both OC and CC mode a Low PPO or High PPO alert is displayed when the
36. epiece To be calibrated out such an object must be mounted with the eyepiece such that the interfering object moves along with the eyepiece Compare the NERD compass with a known good compass or fixed references to determine if calibration is needed If comparing against fixed references remember to consider the local deviation between Magnetic North and True North declination Calibration is not needed when travelling to different locations The adjustment needed then is the True North declination When calibrating rotate the NERD smoothly through as many 3D twists and turns as possible in 20 seconds Keep metal and magnetic objects away during calibration The calibration can also be reset back to the factory values After calibration it is recommended to compare the compass accuracy with a known good compass or fixed references True North Adjustment In most places a compass does not point towards True North but rather to Magnetic North The difference in angle between these two directions is called the magnetic declination also called magnetic variation and varies around the world The declination in your location can be found on maps or online If you only need to match an uncompensated compass or your navigation is all based on relative directions then this setting is not necessary and can be left at 0 SHEARWATER Enable On Calibrate Adjust True North Next Enable On Calibrate Adjust
37. eplate screws Clean with water ONLY Any solvents may damage the NERD dive computer Service of the NERD may only be done at Shearwater Research or by any of our authorized service centers Your nearest service center can be found at www shearwaterresearch com contact Fischer Pin out On the EXT model the Fischer connector pin out is as shown looking into socket on NERD 1 Common GND ah 2 O2 Sensor 1 P4 Cy 4 3 O2 Sensor 2 n 4 O2 Sensor 3 SHEARWATER Shearwater NERD User Manual Specifications Specification External PPO2 EXT Model Operating Modes OC OC CC internal PPO2 OC CC external PPO2 OC SC external PPO2 Gauge B hlmann ZHL 16C with GF VPM B and VPM B GFS optional Accuracy 20 mBar at surface 100 mBar at 14bar a a Accuracy 0 0 83 0000 Roll 45 Pitch 45 135 Range Range 30 Hours AA 1 5V Alkaline Display Medium Brightness 80 Hours SAFT LS14500 External O2 Sensor Type 10mv in air Type Common negative Zero offset Linear response to PPO2 Temp comp in sensor Range OmV to 100mV Weight 0O 35kg 79 QQ SHEARWATER Shearwater NERD User Manual FCC Warning a USA Federal Communications Commission FCC This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of FCC Rules These limits
38. f oxygen FO2 of the calibration gas In CC mode the calibration gas FO2 can be set from 0 70 to 1 00 The default value of 0 98 is for pure oxygen but assumes about 296 water vapor due to the diver s breathing on the loop during the flushing process In SC mode the calibration gas FO2 can be set from 0 20 to 1 00 This is because semi closed divers do not always have oxygen available Note When in SC mode the user cannot utilize internal PPO2 monitoring Sensor Disp Sets the sensor display mode on the center row of the main screen In CC mode the available settings are Large the PPO2 text is the normal large font Giant the PPO2 text is larger In SC mode the available settings are e PPOZ the PPO2 is shown e FiO2 the Fraction of inspired O2 FiO2 is shown e Both PPO2 shown is large font FiO2 below in small font Auto SP Setpoint Switch This menu page is only available in CC mode when PPO2 mode is set to internal see Dive Setup page Auto Setpoint Switch configuration sets up the setpoint switching It can be set up to auto switch up only down only both or neither First you set the whether the Up switch occurs automatically or manually If Up is set to Auto then you can set the depth at which the auto switch occurs Sensor Disp Change 0 960 97 97 CC 21 00 0 0 In SC Mode the center row can show FiO2 instead of PPO2 Auto SP Switch Up be
39. gas then 87 80 84 press the SELECT button to select that diluent gas M C On 21 00 If you increment past the number of gases available the display will fall back out of the Select Gas display without changing the selected gas An A will appear next to the currently active gas A gas that is off will be shown in magenta but can still be selected It will be turned on automatically if it is selected Off gases are not used in decompression calculations Radio Station Gases For computer models that support open circuit and closed circuit operation the system maintains two sets of gases one for open circuit and one for closed circuit The way they operate is very similar to the way car radios work with AM and FM stations When you are listening to an FM station and you push a station selection button it will take you to another FM station If you add a new station it will be an FM station Similarly if you are in the AM mode adding or deleting a station would add or delete an AM station With radio station gases when you are in open circuit adding deleting or selecting a gas will refer to an open circuit gas Just like the FM stations are selected when your radio is in FM mode the closed circuit gases are available in the closed circuit mode When you switch to open circuit the gases available will be open circuit gases 44 QQ SHEARWATER Shearwater NERD User Manual Select Gas Menu Styles Two s
40. he brightness value use SELECT to save the current value Q SHEARWATER Shearwater NERD User Manual Installing the NERD on your Rebreather The NERD is designed to mount on the mouthpiece of your rebreather s breathing loop to ensure the eyepiece is easily viewable when diving It does this with a removable loop mount that provides quick tool free uninstallation of the NERD with the use of a nylon strap and a cam lever The NERD s battery box is designed to mount over your shoulder either on the breathing loop or directly onto your rebreather It attaches with two elastic straps and adjustable buckles fo Steps for Installing the NERD 1 Select a spot on your rebreather mouthpiece to mount the NERD The selected area should be Free of obstructions e Roughly within your natural field of view e Sufficiently stiff to support tightening the NERD s strap e Sufficiently far away from your DSV to ensure that your DSV is not obstructed 2 Adjust the nylon strap to longer than is needed 3 Loop the nylon strap around the rebreather mouthpiece and hook the square metal loop into the cam lever with the cam lever open 4 While holding the plastic buckle pull the loose end of the nylon strap until snug LIA AES 9 Q SHEARWATER Shearwater NERD User Manual 5 Rotate the NERD until it is comfortably aligned within your line of sight 6 Close the cam lever to lock the NERD in place
41. her manufacturer On the PPO2 calibration screen the top row 44 46 47 97 96 a99 displays the millvolt mV reading from each PPO2 sensor The middle row is the current PPO2 Calibration from the last calibration The bottom row shows the fraction of oxygen setting Cal F02 98 After calibration completes a results screen will be displayed Note that the PPO2 might not match the FO2 exactly due to the ambient pressure not being exactly 1 ata Ready a The dive is now ready to begin Dive Hypoxic diluents such as the 10 50 in this example require special training since they can be deadly near the surface Nasan Pressing SELECT brings up the first info Hypoxic screen which shows the diluent PPO2 The red ee indicates it is unsafe to breathe directly You can view this info at any time to verify that the diluent is safe or to check what the expected PPO2 will be when flushing with diluent at depth Continued on next page s Q SHEARWATER Shearwater NERD User Manual Complex Dive Example continued Dive Phase Decreasing NDL Bottom Time Ascending to First Stop First Deco Stop A problem has developed 2 Description NERD Display As we descend the NDL decreases The TTS shows it will take 5 minutes to ascend to the surface at 10m min 33ft min We have now completed the bottom time 90 20 48 The TTS indicates we have about 1 5 hours 30 30 92 minutes of deco
42. ing Pressure The pressure in millibars Two values are shown the surface surf pressure and the current now pressure The current pressure is only shown on the surface The surface pressure is set when the NERD is turned on If the Altitude setting is set to SeaL vl then surface pressure is always 1013 millibars Temperature The current temperature in degrees Fahrenheit when depth in feet or degrees Celsius when depth in meters Battery The NERDSs internal battery voltage Displays in Yellow when the battery is low and needs replacement Displays in Flashing Red when the battery is critically low and must be as soon as possible Also shows battery type Millivolts The raw millivolt readings from the PPO2 sensors Only available when external PPO2 monitoring is used Date and Time In the format dd mon yy 12 or 24 hour clock time Serial Number amp Version Each NERD has a unique serial number The version number indicates the available features The last two numbers are the firmware version V12 in this image 30 85 3 90 42 0 46 0 43 0 28 Jun 12 16 31 28 Jun 12 4 31on 1234ABGD 2000012 QQ SHEARWATER Shearwater NERD User Manual Compass The NERD contains a tilt compensated compass The compass sensor is located in the eyepiece thus indicating whichever direction you are looking Compass features 1 resolution e 3 accuracy e Smooth high speed refresh
43. ion allows you to display four different values during the dive The display can be changed during the dive to provide different information Pushing SELECT will make the NDL display editable The first choice available will be NDL If you select NDL the NDL will always be displayed during the dive whether or not you have a decompression ceiling The next selection is CEIL With this setting as long as the NDL time is 0 you have a decompression ceiling the raw ceiling will be displayed instead of the NDL This is the equivalent of the Man on a rope It will show your ceiling without it being rounded up to the next even 10 foot or 3 meter stop Please note that there is very limited information on the effects of following a continuous ceiling instead of stopping at stops and only moving up to the next stop when the stop has cleared It is the author s opinion that all stops should be honored It seems intuitive that if you have bubbles and you stop you give the bubbles an opportunity to be resorbed If you continuously ascend the ambient pressure is continuously reduced which prevents bubbles from shrinking Because of this belief the computer will give one MISSED DECO STOP message during the dive and one after the dive and will flash the stop depth and time in red as long as you are above the stop depth It will use the increased gradient though and your calculated off gassing will be faster than staying at the stops The ne
44. ion menu the screen will show e Top row Millivolt mV readings from the 3 O2 sensors e Middle row PPO2 values using the previous calibration e Bottom row The calibration gas fraction of O2 FO2 If you need to change the calibration gas FO2 do this in the etup O2 Setup menu After flooding the breathing loop with the calibration gas typically pure oxygen press the SELECT button to perform the calibration Good sensors should be in the range of 35 65 mV at sea level in 100 oxygen so a sensor will fail calibration if not in the range of 30mV to 70 mV This allowable range scales automatically with changes to FO2 and barometric pressure A millivolt reading is shown in yellow if outside the allowable range Once the calibration completes a report will be shown This shows which sensors passed calibration and the value of the expected PPO2 based on barometric pressure and the FO2 Back at the main screen the displays should now all read the expected PPO2 For example if FO2 is 0 98 and barometric pressure is 1013 mbar 1 ata then PPO2 will be 0 98 If any display shows FAIL the calibration has failed because the mV reading is out of range The Calibrate menu item will not display during a dive Q SHEARWATER Shearwater NERD User Manual Single Sensor Mode A single external O2 sensor may be used 46 00 To enter this mode perform the calibration with only the middle sensor connected al
45. ixed position relative to the eyepiece i e it moves with the eyepiece then this effect can be calibrated out using the Calibrate option in the Compass Setup menu Shipwrecks may interfere with the compass reading and so the compass function should not be used near or inside of a shipwreck Use the same discretion and training as you would with a traditional compass Magnetic declination also called magnetic variation is the difference between magnetic and True North This can be compensated in the Compass Setup menu The magnetic declination varies around the world so will need to be readjusted when travelling This adjustment can also be used to compensate if the NERD is mounted with a slight angle to your forward direction Magnetic inclination or magnetic dip is how much the Earth s magnetic field points up or down The NERD compass automatically compensates for this angle However in some locations near the poles the inclination angle can exceed 80 i e the magnetic field points almost directly up or down in which case the specified accuracy may not be met Setup and Calibration See the sub section of Menu Reference section of this manual for instructions on setting up and calibrating the compass 24 SHEARWATER Shearwater NERD User Manual 25 Operating Modes The Mode setting allows tailoring the NERD to specific types of diving Use the right mode to get the best experience from the NERD The foll
46. lashing Red when less than 0 19 or greater than 1 65 The above limits can be adjusted in the Adv Config 2 menu D QQ SHEARWATER Shearwater NERD User Manual Center Row Configuration Unless 3 external PPO2 values are displayed the center row displays can be customized 2202 221130 Center Gas PP02 Custom Right None Display 225 1 15 Next Configure the center row in the System Setups Center Row Menu The left and right positions can be set to display the following Option Descripion Ceil The current decompression ceiling not rounded to the stop interval NS GF99 The B hlmann ZHL 16C super saturation percent gradient Central Nervous System CNS toxicity clock as a percentage Clock The time of day in 24hr or am pm format same as system setting Does not show am or pm DET Dive End Time The time of day when the dive will end i e Clock plus TTS In 24hr or am pm format same as system setting Does not show am or pm The diluent PPO2 at the current depth Only available when CC is available FiO The fraction of inspired O2 as a percentage Only available when CC or SC is available 2 The water temperature The center position can only display PPO2 In OC only mode the PPO2 display can optionally be turned off Unfortunately customization is not possible when using External PPO2 monitoring of three O2 sensors as all the space is already used
47. le It will use the next available gas that has a PPO2 of less than 1 6 for open circuit diving NOTE These gases are used automatically only for TTS predictions The gas used to calculate the current tissue load and the current ceiling is always the gas actually selected by the diver Q SHEARWATER Shearwater NERD User Manual Decompression and Gradient Factors The basic decompression algorithm used for the computer is B hlmann ZHL 16C It has been modified by the use of Gradient Factors that were developed by Erik Baker We have used his ideas to create our own code to implement it We would like to give credit to Erik for his work in education about decompression algorithms but he is in no way responsible for the code we have written The computer implements Gradient Factors by using levels of conservatism The levels of conservatism are pairs of number like 30 70 For a more detailed explanation of their meaning please refer to Erik Baker s excellent articles Clearing Up The Confusion About Deep Stops and Understanding M values The articles are readily available on the web You might also want to search for Gradient Factors on the web The default of the system is 30 70 The system provides several settings that are more aggressive than the default Don t use the system until you understand how it works Pressure Graph Gradient Factors A Gradient Factor is simply i 5 5 d 1 decimal fraction or percent
48. limits are violated for more than 30 seconds 68 Q SHEARWATER Shearwater NERD User Manual 69 Firmware Upload and Dive Log Download Bluetooth communications are used for both Firmware Uploading and Dive Log Downloading NOTE Upgrading the firmware resets decompression tissue loading Plan repetitive dives accordingly Download amp Install Shearwater Desktop http www shearwaterresearch com downloads Available for Windows and Mac Plug the Bluetooth Dongle into a USB Port Most Macs have built in Bluetooth so Mac users do not need to use the supplied dongle Download the New Firmware http www shearwaterresearch com downloads Firmware file end with aes Save it on your computer somewhere you can find it later On the NERD start a Bluetooth Connection Bluetooth can be started in two ways Dive Log Upload Log OR System Setup System Setup Load Upgrade Both options do the same thing They turn on Bluetooth and wait for commands from your desktop or laptop Go to the next step once the 3 minute Nowi ready tor countdown begins Bluetooth connection Load Upgrade Reset to Defaults QQ SHEARWATER Shearwater NERD User Manual In Shearwater Desktop go Dive Computer Update Firmware f Shearwater Desktop File Edit Dive Computer Help Com MES ne Ctrl U Location Sit e 267 Download Dive Log Ctrl I Update Start Up Text Ctrl L 267 24FFCCAD 23 06
49. mpression to do The first stop will be at 48m for 1 minute Here we are ascending at 3m min each bar 61 6 29 48 beside the depth is 3m min This is slower TS than the expected 10m min ascent rate 1 29 1 28 This slow ascent has caused the TTS to rise as most tissues are still on gassing The slow ascent has caused the first stop to clear before we reached it This often happens with slow ascents A i 3 34 4 Note that the GF99 value now indicates that 30 32 the leading tissues are now off gassing However at this deep depth most tissue compartments are still on gassing The yellow cell reading is disagreeing with the other two A flush with diluent has shown that the lone low cell is actually correct It is decided to bailout to open circuit Continued on next page SHEARWATER Shearwater NERD User Manual 33 Complex Dive Example continued Dive Phase Description NERD Display Bailout Switch Gas Deco Clear After physically switching the BOV or mouthpiece the computer needs to be set to OC mode for proper deco calculations Two presses on MENU brings up the SWITCH CC gt OC menu Pressing SELECT makes the change Note that the loop PPO2 continues to display This is important in case the diver later needs to go back onto the loop Also note that OC is displayed in yellow to indicate the bailout condition The best OC gas was automatically selected and the d
50. nd 2 this device must accept any interference including interference that may cause undesired operation of this device L utilisation de ce dispositif est autoris e seulement aux conditions suivantes 1 il ne doit pas produire d interference et 2 l utilisateur du dispositif doit tre pr t accepter toute interference radio lectrique recu m me si celle ci est susceptible de compromettre le fonctionnement du dispositif Caution Exposure to Radio Frequency Radiation The installer of this radio equipment must ensure that the antenna is located or pointed such that it does not emit RF field in excess of Health Canada limits for the general population consult Safety Code 6 obtainable from Health Canada s website www hc sc gc ca ewh semt pubs radiation radio guide lignes direct eng php sc6 Contains TX IC 216QEbzzMU 80 SHEARWATER
51. nt above 0 Another use would be to observe the rapidly Pressure Graph Gradient Factors increasing gradient in the last 10 feet to the TE surface and slow that ascent T GF Lo generates first stop All of this is based on gradient theory that may be completely false There is significant disagreement in the decompression research community about the nature and practice of decompression Any techniques described here should be considered experimental but the concepts may be useful to the advanced diver ae ee NE linear function for gradual change in Gradient Factors Compartment Inert Gas Pressure absolute GF Hi surfacing value maintains safety margin First Stop o The last selection is 5 This feature was inspired by Dan Wible s CCR2000 computer Thanks Dan It is the time to surface TTS if you were to stay at the current depth for five more minutes This can 85 86 84 be used as a measure of how much you are on gassing or off gassing Display 5 e ave For example on a dive on a wreck you go to the bottom until you accumulate the desired decompression and TTS After ascending to the second deck you notice that the 5 and TTS are the same That means that you can spend 5 minutes exploring this deck without incurring more decompression Once you get to the top deck the current has picked up The line runs from the top of the deck to the surface which is a distance of 30 fee
52. of the NERD Loop Mount using a 1 16 hex key not provided Slide the Loop Mount towards the NERD 1 16 Hex Key 74 SHEARWATER Shearwater NERD User Manual Tissues Cleared Some conditions will cause the decompression inert gas tissue loadings to be cleared When cleared the tissues are set to being saturated with breathing air at the current barometric pressure The NERD does not lock out when the tissues are cleared If the tissues are cleared then the diver must take appropriate cautions when planning repetitive dives The NERD clearly notifies when tissues are cleared so that the diver has the proper information to make responsible decisions For example after changing the battery you will see one of these two screens Battery Changed Battery Changed Conditions that cause the tissues to be cleared are Firmware Updates A firmware update will clear the tissues Therefore updating the firmware in the middle of a dive trip is not a good idea User Request You can clear the tissues manually in the System Setups System Setup menu Use the Reset To Defaults option This will then prompt if you want to reset the settings only the tissues only or both Slow Battery Change Quick battery changes do not normally cause the tissues to be cleared A super capacitor stores energy to keep the clock running for at least 15 minutes during a battery change If battery removed for longer than 15 minutes then the tiss
53. om 0 to 5 with higher numbers being more conservative Next Edit Last Stop Allows you to chose where to do your last stop The choices are 10ft 3m and 20ft 6m Note that this setting does not affect decompression It only makes the TTS prediction more accurate NDL Display These options were previously covered in the Dive Setup section OC Gases The next submenu is OC Gases This menu allows the user to edit the open circuit gases The options contained here are the same as those in the Define Gases subsection of the Dive Setup section contained earlier in this manual The interface conveniently displays all five gases simultaneously For a description of how to appropriately set each gas please see the above Define Gas section CC Gases The next submenu is CC Gases This menu allows the user to edit the closed circuit diluent gases The options contained here are the same as those in the Define Gases subsection of the Dive Setup section contained earlier in this manual The interface conveniently displays all five gases simultaneously For a description of how to appropriately set each gas please see the above Define Gas section Q SHEARWATER Shearwater NERD User Manual O2 Setup This menu page is only available in Closed Circuit CC or Semi Closed SC mode when PPO2 mode is set to external see Dive Setup page Cal FO2 This setting allows you to set the fraction o
54. om the internet Have more gradual voltage drop as discharged so easier to determine remaining capacity than NiMH rechargeables Good in cold water NOTE Battery operating lifetimes are given with screen on medium brightness and at room temperature Higher brightness and lower temperature can reduce life Lower brightness can increase life 72 Q SHEARWATER Shearwater NERD User Manual Threading the NERD s Strap If for any reason the nylon strap of your NERD becomes un threaded use the following instructions to re thread it through the hardware provided with your NERD 1 Start with the supplied hardware including two metal square loops the nylon strap sewn onto the buckle and the strap keeper as shown below Square Metal Loop 2 Thread the free end of the nylon strap through the metal loops buckle and strap keeper as shown below 73 SHEARWATER Shearwater NERD User Manual Disassembling the Loop Mount The loop mount including the cam lever that attaches to your rebreather mouthpiece can be removed from the NERD You may wish to do this if your loop mount is in need of repair or replacement or if you wish to mount your NERD on an alternative mount developed by Shearwater or a 3rd party mounting system For technical assistance developing 3rd party mounting systems for the NERD contact us at support shearwaterresearch com To disassemble the loop mount Remove the setscrew from the underside
55. oues etootitasdeigieninii bl accti cic baasat Kin MG DiRTR Mu drU IC dL DU EN Era rd eU REP DEDIT UM D NE 27 Simple Dive Example sssssnsnsxx naria anra ocior ncmo nna 28 Complex Dive Example sacssicssscsssnccsssscnsdsscdsssstassncscdeansenstesucessssanssceudsdscsanaatnusnsensanseasnns 30 LLL L PmeT 34 Open Circuit Menu iei is re de M RT 35 Closed Circuit Int PPO2 Menu Structure sass tsececacinenilisseniswadancecitandatensleade deuvsiadiabiadabausathadsiatiasdsinsd 36 Closed Circuit Ext PPO2 Menu Structure icicciccccccccseccsssccssccsccseessessesescessseessesssceusseaeseeseeess 37 Gatge Menu Struct rE rrenan an ae ashen lanra aaae NIAL EETAS 38 EEIE i o E E 39 Decompression and Gradient Factors ssscssssssssssseessccsessenssseneessenesseensssennssennessnnessens 40 Menu Reference snis iD ERO Hop ODER RD ER ER COENA ERR RENDERE DR RR ERR RC 41 NEP pid uU NRDTER e T 41 lere id d MR RIT NRI RC DECORE CR ERECTO NORTE NR PRO PEST 41 Single Sens r NOS T c aa nand e d Ei pEi 42 Calibration PrOD IeN IS scnsisiccssacnsdcaeseaepeieensusesdocecssangeaeuddseudseesipessnonsadsuasebes FEES n iiias aS 42 SUCH SOS DUBIE esrara aA uU Ad Aea aaa aa sd Co nb Taaa aa aae a no cedo EI 43 Select GIS a aa assets bile de etapa anaes A AE 44 Radio Station GaSe Sgine e i Eaa aa aa apaa Kd C ad MD pd CEDENS 44 Select Gas Menu Styles rcns es eg s
56. owing modes are available Mode Description ST OC SC Semi Closed Circuit with Open Circuit bailout Depth and time display No decompression PPO2 Like Gauge but with PPO2 display No decompression Each mode optimizes the main screen display and menu options for the specified style of diving See the Menu Reference gt System Setup Section for changing the mode The following images show the main screen in each mode Mode Name Main Screen Mode Description 0205 22 130 1 OC Open Circuit Use when not diving a closed circuit rebreather Simplifies operation by removing unneeded menus and displays OC 2204 22 130 OC CC Closed Circuit with OC bailout OC CC 20 22 Can use either external PPO2 monitoring or fixed internal PPO2 setpoints Continued on next page Q SHEARWATER Shearwater NERD User Manual PIE 22 36 OC CC 2 III II 1 21 130 i 56 220a 221140 OC SC 1 20 1 22 Gauge PPO2 242 138 16 45 26 Mode Description OCICC 2 Closed Circuit with OC bailout Alternate layout Larger depth and time but less information than normal CC mode Reverts to normal OC layout when in bail out View the diluent gas on the first info screen press SELECT OC SC Semi closed Circuit with OC bailout Decompression is calculated different in SC mode versus CC because the projected PPO2 at shallower depths is different Only external PPO2 monitoring is available Ga
57. p to 99 9m Note If the depth shows a Flashing Red zero then the depth sensor needs service Ascent Bar Graph Shows how fast you are currently ascending Imperial 1 arrow per 10 feet per minute fpm of ascent rate Metric 1 arrow per 3 meters per minute mpm of ascent rate White when 1 to 3 arrows Yellow when 4 to 5 arrows and Flashes Red when 6 arrows or more Note Deco calculations assume 33fpm 10mpm ascent rate Dive Time The length of the current dive in minutes The seconds display as a bar drawn below the word Time It takes 15 seconds to underline each character in the word Does not display the seconds bar when not diving Battery Icon Yellow when the battery needs to be changed Red when the battery must be replaced immediately The default behavior is that battery icon is shown on the surface but disappears when diving If low or critical then the battery icon will appear while diving in feet in meters 30 fpm 9 mpm 50 fpm 15 mpm 60 fom 15 mpm in minutes seconds bar at about 45s OK low battery now 2 SHEARWATER Shearwater NERD User Manual Stop Depth and Time Stop The next stop depth in the current units feet or meters This is the shallowest depth to which you can ascend 00 2 Time The time in minutes to hold the stop Stop at 90ft for 2 min Will Flash Red if you ascend shallower than the current stop Ji By default the NERD uses a
58. rate User set heading marker with reciprocal True North declination adjustment e Tilt compensation e 45 roll e 45 to 135 pitch Sp Tilt Compensation Tilt compensation algorithms for digital compasses can typically only compensate well for up to 45 of tilt on the pitch and roll axes This is fine for roll but when diving the pitch angle changes 90 as you move from being vertical in the water to being prone in a swimming position To compensate for this large pitch angle variation the NERD assumes that your direction heading shifts as you move from the vertical to prone position When vertical your direction is taken extending straight out your nose When prone your direction is taken as extending out the top of your head Close to the swich over point both headings are averaged to prevent a discontinuity The figure below illustrates this best 0 From 45 to 45 pitch direction is taken facing forward From 45 to 135 pitch direction is taken extending out the top of your head 90 Outside these ranges The NERD tilt compensates over a wide range by redefining your heading when prone 135 22 accuracy is not guaranteed Most divers will find this a natural way of interpreting direction Q3 SHEARWATER Shearwater NERD User Manual Viewing the Compass When enabled the compass is viewed by pressing the SELECT right button once Press SELECT again to continu
59. reen and press the SELECT button a few times displays as Pressure mBar NOW surr 000 non 990 42 Q SHEARWATER Shearwater NERD User Manual Switch Setpoint This menu is only available in CC mode when PPO2 mode is set to Int internal The internal PPO2 mode is used to calculate decompression for a unconnected rebreather In this case the setpoints are switched in the computer to approximate the rebreather setpoint During a dive the Switch Setpoint menu item will be the first item displayed since the Turn Off and Calibrate displays are disabled when diving Pressing SELECT when this menu is displayed changes the PPO2 setpoint from the low setpoint to the high setpoint or vice versa To redefine the PPO2 value of a setpoint use the Dive Setup menu This menu item performs a manual switching of PPO2 setpoint In the System Setups Auto SP Switch menu the NERD can be setup to automatically perform setpoint switches at programmable depths When auto setpoint switches are enabled this menu item is still available to provide manual control 43 Q SHEARWATER Shearwater NERD User Manual Select Gas This menu item allows you to pick a gas from the gases you have created The selected gas will be used either as the breathing gas in open circuit mode or the diluent in closed circuit mode Gases are always sorted from most to least oxygen content Use the MENU button to increment to the desired diluent
60. sion information has been lost This alarm happens when the computer does not complete all of its tasks in the time allotted It can happen occasionally from a 45 transient problem like a battery bounce after an impact It can also 1 30 l 32 l 3 be the result of a hardware problem g i This reset shows up after a software update This is the normal 45 event that shows the computer has been rebooted after the 3 b I 3 software update This is not an exhaustive list Please contact Shearwater if you experience any unexpected errors The center row also shows permanent Low PPO2 or High PPO2 messages when the PPO2 is not in a safe range These message will clear automatically once a safe PPO2 is restored Sample Errors on Center Row 77 QQ SHEARWATER Shearwater NERD User Manual 78 Storage and Maintenance The NERD dive computer should be stored dry and clean Do not allow salt deposits to build up on your dive computer Wash your computer with fresh water to remove salt and other contaminants Do not use detergents or other cleaning chemicals as they may damage the NERD dive computer Allow to dry naturally before storing Do not wash under high pressure jets of water as it may cause damage to the depth sensor Store the NERD dive computer out of direct sunlight in a cool dry and dust free environment Servicing There are no user serviceable parts inside the NERD Do not tighten or remove the fac
61. system average PPO2 is the average PPO2 of sensor 1 and 2 If all sensors fail voting then the display will alternate VOTING FAILED with the PPO2 measurements which will all be yellow to indicate that voting has failed When voting has failed the lowest PPO2 reading will be used for deco calculations i e the most conservative value Switching to Open Circuit bailout with External PPO2 Monitoring If you bailout to OC mode the external PPO2 will continue to display on the main screen However the system PPO2 used for deco calculations will change to OC mode i e PPO2 is the fraction of O2 multiplied by the current depth s pressure The external PPO2 continues to display because the diver may need to return to the loop and will need to know the PPO2 status of the loop even though the sensor input is not being used as the system PPO2 0 J PP 2 Mode Change 0 96 97 Pit Ki Ext Save 0 LEM CC 21 00 0 0 EMI ni QQ SHEARWATER Shearwater NERD User Manual 56 If we now unplug sensor 1 and sensor 3 the computer will use voting logic to pick the two sensors that agree and will think the PPO2 is 0 Sensor 2 will be voted out and flashing yellow This is a limitation of voting logic and the user will have to determine which sensors are correct With sensors one and three unplugged we simulate the situation of single sensor monitoring If we in this situation the system will assume that this compu
62. t 10 m You see that your 5 is 11 minutes and your TTS is 15 minutes That means that you can stay down out of the current for 5 minutes and burn off about 4 minutes of deco You may decide to accept the 80 decompression efficiency and stay out of the current When your TTS is 10 minutes you see that your 5 is 9 minutes Since the decompression is not very efficient now you go up the line and spend the last 10 minutes in the current 54 QQ SHEARWATER Shearwater NERD User Manual External PPO2 Monitoring The next menu item is used to turn external PPO2 monitoring on and off By default external monitoring is turned off and reads Int for Internal fixed setpoint mode This setting can be changed to Ext to enable external PPO2 monitoring from oxygen sensors Now the PPO2 of the three sensors is displayed A valid calibration must have been previously performed see the Calibration section This system is plugged into three sensors and using the PPO2 input from the sensors as the system average PPO2 used for decompression calculations and CNS tracking A voting algorithm is used to decide which of the three sensors are likely to be correct If a sensor matches either of the other two sensors within 20 it passes voting The system average PPO2 is the average of all sensors that have passed voting For example here sensor 3 has failed voting The PPO2 is displayed in yellow to show that it has failed voting The
63. t a submenu listing MENU Fxanple will be used to change the context sensitive variable while the pats SELECT button will be used to move to the next field Once the user MEE has pressed SELECT through all the fields the new user preferences will be saved 58 QQ SHEARWATER Shearwater NERD User Manual 59 Dive Setup The first submenu of System Setup is Dive Setup Mode Mode Salinity Mode sets which breathing circuit configurations are available PPO2 Mode OC CC default e OC OC SC only on models with external PPO2 connector Gauge e g bottom timer mode Important information for OPEN CIRCUIT divers All NERD models include Closed Circuit CC functionality Leaving CC mode enabled makes the NERD more complex and less optimized for OC diving Switch Mode from OC CC to OC before performing an open circuit only dive Also when CC mode is available then OC is treated as bailout This is why OC is shown as a yellow warning when CC mode is available When changing to or from Gauge mode the decompression tissues are cleared This is because when in Gauge mode the NERD does not know what gas you are breathing Salinity Water type salinity affects how the measured pressure is converted to depth Settings Fresh EN13319 Salt Fresh and Salt water differ by about 3 Salt water being denser will display a shallower depth for the same measured pressure versus the Fresh water set
64. t each cen inepe ieii eps bee sessed se EEEE aeaaea 45 c reine ie M 46 2 Q3 SHEARWATER Shearwater NERD User Manual Table of Contents continued PM 46 LOW SO WOU iioac diio sr REFERO E E a a A HERE TETREFFRE US 46 PUN MO OUI c 47 Delne SAS NN ONE ER 48 IBI ed zc RR DR Sc 50 CONS EVV All SE NT 52 NDL DISplay gee 53 Exitemal PIOS IIOIOIFID sssini sororia raataa P aee EOeLapUTt a U GER pHE Ede ence ape E e Ee EU Heo 55 BINNES S ceed a S ee e aaaea een erate 56 Dive LOT a A E a aa 57 BIE 8 f SY a Kole E E 57 VINSE O MELo RE E E E E E T 57 Edit L g NUMDET RERO ERR 57 System SSt P NR Te en nn EO eaaa aa ek aa ea aai COR RD 58 Diye Setup T yee nyt etree 59 SSID recie a E E 61 OC Gases aaa a E 61 CC Gases aerea ae E E E 61 O2 S6lUP c a e M 62 Ee teriseDnibolie e EEE Eoia 62 POTS ley SS UD M NEN RR E TT T TOU 63 C mpass SEU soens rosii on ove ree E aL EP Erud ce P Se ree en eer Rae NER E 65 Systemi NS UI C o 66 Advanced Configuration M T mm UU aE Ea HDR
65. tage of the B hlmann allowable supersaturation at the current depth 2 5 The predicted time to surface TTS if you were to stay at the current depth for 5 more minutes Time to Surface TTS The time to surface in minutes This is the current time to ascend to the surface including the ascent plus all required deco stops e B g o on fom ceo Assumes e Ascent rate of 33 feet per minute 10 meters per minute e Decompression stops will be followed e Programmed gases will be used as appropriate The bottom row is also used to show additional information By using only the bottom row for this additional information the critical information contained on the Top and Center Rows is always available during a dive The additional information that can be displayed on the bottom row includes Info Shows additional dive information Screens Press SELECT right button to step through info screens Menus Allows changing settings Press MENU left button to enter menus Warnings Provide important alerts Press SELECT right button to clear a warning 220 221130 1 19 234i 190 6 Sample Info Screen Sample Menu Sample Warning The bottom row is used to display additional information 7 SHEARWATER Shearwater NERD User Manual Info Screens Info screens display on the bottom row Press SELECT right button to step through the info screens N SELECT button Q3 2 7 1 N SELECT button
66. ter is only attached to one sensor and will re configure for fourth sensor monitoring It will no longer average the sensors or vote on them Now the single sensor is the only one considered and the PPO2 used for calculations is the PPO2 of the single sensor Brightness The display brightness has three fixed brightness settings The fixed options are Low Longest battery life Med Best mix of battery life and readability High Easiest readability especially in bright sunlight Q SHEARWATER 85 06 Brightness Exit 84 ll Edi Shearwater NERD User Manual 57 Dive Log Display Log At the Display Log prompt press SELECT to view the most recent dive The profile of the dive is plotted in blue with decompression stops plotted in red The following information is displayed Maximum and Average depth Dive number Date mm dd yy Start Time of day that the dive started End Time of day that the dive ended Length of dive in minutes Press MENU to see the next dive or SELECT to quit viewing logs 339ft Gmin r Max eee 5 43pm Press Back to see the list of dive logs and next to select the Te sere 5 49pm next dive and View Upload Log See Firmware Upload and Dive Log Download instructions Logs are uploaded using Bluetooth Selecting this menu item starts the Bluetooth connection and then waits for commands from a desktop or laptop computer Edit Log Number
67. thing that had been previously saved will be retained Anything that was in the middle of editing will be discarded Adaptive Menus Only menus necessary for the current mode are shown This keeps operation simple prevents mistakes and reduces buttons presses 34 QQ SHEARWATER Shearwater NERD User Manual 22 The following sections show the menu structure in various operating modes Open Circuit Menu Structure Surface only Surface only Surface only System Setupt Sub Menus NDL Displa Upload Log Edit Log Number 00 Gases Display Setup System Setup Advanced Config SHEARWATER Shearwater NERD User Manual 36 Closed Circuit Int PPO2 Menu Structure Dive Logt System Setupt Sub Menus Edit Low SP Edit High SP C Define Gas C Display Log Upload Log Edit Log Number C Dive Setup C Deco Setup C Genter Row COC bases Q3 SHEARWATER Dive Planner Conserv C NOL Display PPP Mode Brightness GET Ne Auto SP Switch Display Setup C System Setup Advanced Config Shearwater NERD User Manual Closed Circuit Ext PPO2 Menu Structure 2 Dive Logt System Setupt af Edit Log Number Sub Menus NDL Displ
68. ting The EN13319 value is between Fresh and Salt It is from the European CE standard for dive computers and is the NERD s default value QQ SHEARWATER Shearwater NERD User Manual PPO2 Mode PPO2 mode is only set when CC is enabled This value can be set to either Int Internal fixed PPO2 set points Ext External measured PPO2 The PPO2 Mode can also be changed even during a dive in the Dive Setup menu When semi closed circuit SC is used the PPO2 mode must be Ext Low and High Setpoints The Low and High PPO2 Setpoints are only available when CC is enabled and PPO2 Mode is Internal Each setpoint can be set from 0 4 to 1 5 The setpoints can also be edited even during a dive in the Dive Setup menu 60 Q SHEARWATER Shearwater NERD User Manual 61 Deco Setup Deco Model May just show B hlmann ZHL 16 with gradient factors model or it may allow you to switch between GF and various types of VPM B The Deco Setup i i i i Deco Model GF choices will be available if you have unlocked VPM B Conserv GF 30 70 Last Stop 6m NDL Display CEIL Conservatism Can be adjusted in either the GF or VPM model For a more detailed explanation of their meaning for the GF algorithm please refer to Erik Baker s excellent articles Clearing Up The Confusion About Deep Stops and Understanding M values The articles are readily available on the web VPM B has conservatism settings fr
69. tyles of Select Gas menus are available Classic and New Change between the two styles in the Adv Config 1 menu Classic Style Select Gas The classic Select Gas style is as described on the previous page One gas is shown ata time Press MENU to step through gases and SELECT to select the shown gas Gases are sorted from highest O2 to lowest 02 Stepping past the last gas will exit the menu without changing the active gas Upon entering the Select Gas menu the first gas shown is always the highest O2 gas New Style Select Gas The new style makes visualizing the gas list easier It also reduces button presses for deco gas switches 45 Shows all gases on the screen at once Press MENU to step through gases and SELECT to select the pointed to gas A gas must be selected to exit the menu scrolling past last gas wraps back to first gas The active gas is shown with a white background Turned off gases are shown in magneta purple Gases are sorted from highest 02 to lowest 02 When diving and there is a deco stop the first gas pointed to will be the most appropriate gas highest PPO2 less than 1 61 This reduces button presses in most cases On the surface or when no deco stops are needed the first gas pointed to will be the active gas Adv Config 1 Title Color End Dive Delay 060s Bat Icon Always Gas Select Classic 21 4 22 21 06 QC On 50 00 Next Gas Select Classic Select Gas
70. ue compartment is shown on the top and the slowest on the bottom Each bar is the combined sum of the nitrogen and helium inert gas tensions Pressure increases to the right The vertical black line shows the inert gas inspired pressure The boundary between the green and yellow zones is the ambient pressure The boundary between the yellow and red zone in the ZHL 16C M Value pressure Note that the scale for each tissue compartment above the green zone is different The reason the bars are scaled in this way is so that the tissues tensions can be visualized in terms of risk i e how close they are as a percentage to B hlmann s original super saturation limits Also this scale changes with depth since the M Value line also changes with depth NO uum 16 tissue 2 T t Inspired inert M Value pressure gas pressure Ambient pressure Increasing pressure Some Sample Tissues Graphs On surface sat with air After descent On gassing Deep stop Last deco stop Q SHEARWATER Shearwater NERD User Manual Gradient Factor The deco conservatism value when the deco model is set to GF The low and high gradient factors control the conservatism of the B hlmann GF algorithm See Clearing up the Confusion About Deep Stops by Erik Baker VPM B and VPM BG The deco conservatism value when the deco model is set to VPM B If the deco model is VPM B GFS also displays the gradient factor for surfac
71. ues will be cleared Corruption A 32 bit cyclic redundancy check CRC is used to verify the integrity of the tissues each time the NERD is turned on If corrupted the tissues will be cleared The most likely cause of corruption is removing the battery with the NERD turned on Therefore turning the NERD off before changing the battery is the best practice Changing To From Gauge Mode In gauge mode the NERD does not know what gas you are breathing and cannot track tissue loading Therefore when changing to or from gauge mode the tissues are cleared 75 Q SHEARWATER Shearwater NERD User Manual Error Displays The system has several displays that alert an error condition A Limitations of Alarms All alarm systems share common weaknesses They can alarm when no error condition exists false positive Or they can fail to alarm when a real error condition occurs false negative So by all means respond to these alarms if you see them but NEVER depend on them Your judgement education and experience are your best defenses Have a plan for failures build experience slowly and dive within your experience Each of the alarms will display the message in yellow until dismissed The error is dismissed by pressing SELECT This message will appear if the average PPO2 goes above 1 6 for more than 30 seconds This message will appear if the average PPO2 goes below 0 4 19 for OC or SC for more than 30 seconds It is
72. uge A simple bottom timer No decompression displays With large depth and time including seconds Stopwatch function plus resettable average depth PPO2 A simple bottom timer that also shows external measured PPO2 No decompression displays With large depth and time including seconds Stopwatch function plus resettable average depth Q3 SHEARWATER Shearwater NERD User Manual Gauge Mode Gauge Mode turns the NERD into a simple depth and time display a k a a bottom timer Change to Gauge Mode in the System Setup Dive Setup menu Since decompression tissues are not tracked in Gauge Mode changing to or from Gauge Mode resets the deco tissues Features Extra Large Depth Display in feet or meters Extra Large Time Display in minutes seconds e Maximum and Average Depth on main screen Stopwatch Resettable Average Depth The Gauge display is organized as Depths along the left Times along the right Most important information Depth Dive Time on the top row Stopwatch The Stopwatch is only available in Gauge Mode When diving starting or stopping the Stopwatch is the first menu option When stopped the word Stopwatch displays in red When non zero the stopwatch can be reset Reset behavior depends on state e If running when reset it continues running counting up again from 0 If stopped when reset then it is set 0 and remains stopped Resettable Average Depth
73. xt option is to display the actual supersaturation gradient for a pure B hlmann 99 99 profile The selection is GF99 With this setting as long as the NDL time is 0 you have a decompression ceiling the gradient will be displayed instead of the NDL The number shown is the percentage of supersaturation The number is calculated by reference to the Ambient Pressure Line and the M Value line It can be thought of as the current GF but it is different in a couple of ways First the current GF generates stops rounded to the nearest 10 feet or 3 meters So a gradient of 40 may reflect a ceiling of 15 feet but the computer will show a rounded up 20 foot stop LAE EM NDL Display NDL Edit LAE EN DL Display MDL Save Display 3 1 15 24 1 1 12 98 9 Q SHEARWATER Shearwater NERD User Manual This number can be used in several ways First it can be used to calculate an aggressive ascent that still has some justification in decompression science For example if a diver were to lose a significant portion of their gas and needed to get shallow fast they could ascend until they reached a gradient of 90 then stop until it dropped to 80 then ascend to 90 again etc That would produce a B hlmann like profile with very little conservatism In an emergency that may be an acceptable risk Another use might be to do a slower ascent on a dive to sightsee but to stay in the decompression zone by keeping the gradie

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